Justification:
Listed as Critically Endangered because of a drastic population decline, estimated to be more than 80% over the last ten years, inferred from the apparent disappearance of most of the population, perhaps linked to chytridiomycosis and/or a combination of mining activities and the chytrid fungus; and because its extent of occurrence is estimated to be much less than 100 km², all individuals are in a single location, and there is a projected continuing decline in the quality of its habitat and the number of mature individuals in northwestern Peru.

This species is known only from the type locality (and single threat-defined location): Quebrada Los Alisos, in the vicinity of Pataz, Pataz province, region of La Libertad, in an inter-Andean valley of the northern portion of the Cordillera Central in northwestern Peru, at an elevation of ca 2,500-3,000 m asl (Venegas et al. 2008). Its extent of occurrence, though unquantified, is estimated to be less than 100 km2.

Live adults and tadpoles could be observed at the type locality until 1999; that year a total of three live adult individuals, five recently deceased individuals and several decomposing bodies were found (A. Catenazzi pers. comm. November 2010). Surveys conducted in 2000 failed to detect adult Atelopus patazensis and only a single tadpole was found in a small pool along the main stream channel (Venegas et al. 2008). More recently (July 2010), extensive surveys were able to locate two individuals of this species again (L. Rodriguez pers. comm. July 2010; J.C. Jahuanchi pers. comm. November 2010). No further adult individuals have been observed since this date, although there is an unverified sighting of one adult individual in 2012 at Llacuabamba, approximately 40 km south of Pataz (A. Catenazzi pers. comm. March 2013).

Individuals collected in 1999 have tested positive for the presence of chytrid fungus. In addition, there was a mining concession in the near vicinity of the stream at the time of earlier surveys (Venegas et al. 2008), and there are currently informal mining activities that introduce mercury into streams (A. Catenazzi pers. comm. November 2010), as well as domestic waste in the stream itself and on the stream banks (J.C. Jahuanchi pers. comm. November 2010). A report by the Peruvian Ministry of Energy and Mines (Ministerio de Energia y Minas 1997) indicates that heavy metal concentrations exceeded standard concentrations in the nearby localities of Parcoy and Laguna Pias. While Parcoy may be more heavily impacted than Los Alisos due to a greater concentration of larger mines and subsequent runoff (A. Catenazzi pers. comm November 2010), the report acknowledges that there is potential for further spread of water pollution. It is likely that these threats have increased in recent years (A. Catenazzi pers. comm. March 2013).

No conservation actions are currently in place for this species, but there is an urgent need to protect the species' type locality and habitat from degradation and alteration caused by water pollution. More information on this species' distribution, population status, natural history and threats is needed, which would help in the establishment of a monitoring programme to assess and track population status and trends, in the screening for presence of chytrid fungus, and in investigations into whether this species may be amenable to captive breeding efforts, to assess the species' capacity to withstand and adapt to ex situ conditions.